How big is a problem of animal suffering? This depends on the numbers of animals involved. The total magnitude of animal suffering may be quantified with the equation:

Magnitude of welfare problem

=

Severity

x

Duration

x

Numbers.

For most wild-caught fish, and also most farmed fish, during capture and subsequent processing the severity and duration of suffering will be high. Most wild-caught fish are likely to die from being crushed in nets or from suffocation, freezing or live dissection after landing. This process will probably take many minutes, or even hours. Most of the world’s farmed fish are also killed by slow and inhumane methods.

The following studies estimate the numbers of fish killed globally each year in fishing and fish farming, using FAO fisheries capture and aquaculture production tonnages together with estimated mean weights for fish species. It is estimated that, each year:

970 – 2,700 billion fishes are caught from the wild, of which

450 – 1,000 billion fishes are caught to make fishmeal and fish oil.

37 – 120 billion farmed fish are killed for food.

170 – over 400 billion farmed decapod crustaceans are also killed for food.

These huge numbers mean the treatment of fishes in commercial fishing and fish farming are major animal welfare issues. These estimates are discussed below:

Using the same method of estimating fish numbers from reported aquaculture production tonnages, it is estimated that between 38 and 128 billion farmed fish were killed for food globally in 2011. Details of the estimate are available for global production and by country.

Numbers of wild fish caught for reduction to fish oil and fishmeal

The above study to estimate numbers of farmed fish also estimates that, on average each year for 2005-2009, between 0.45 and 1.0 trillion* (ie 450,000,000,000 – 1,000,000,000,000) wild fish were caught for reduction to fish oil and fishmeal, mainly used to feed farmed fish.

Using the same method as that used to estimate farmed fish numbers, the numbers of decapod crustaceans killed in recorded aquaculture production in 2011 have been estimated as follows:

21-40 billion* crayfish, crabs and lobsters

150-380 billion shrimps and prawns.

Details of the estimate are available for global production and by country. Welfare issues in crustacean farming include inhumane methods of killing, live marketing and long distance transport. Breeding stock of shrimp and prawn species are subjected to eyestalk ablation to increase egg production. See Welfare of crustaceans.